release: add -w and -f options

1 files changed, 77 insertions, 2 deletions

diff --git a/bin/release_ts.c b/bin/release_ts.c
index 4d4c9e8..9740df2 100644
--- a/bin/release_ts.c
+++ b/bin/release_ts.c
@@ -2,24 +2,90 @@
 #include <stdio.h>
 #include <unistd.h>
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
 #include "litmus.h"
 
-#define OPTSTR "d:"
+#define OPTSTR "d:wf:"
 #define NS_PER_MS 1000000
 
+#define LITMUS_STATS_FILE "/proc/litmus/stats"
+
 void usage(char *error) {
         fprintf(stderr,
                 "%s\n"
-                "Usage: release_ts [-d <delay in ms>]\n",
+                "Usage: release_ts [OPTIONS]\n"
+                "\n"
+                "Options: -d  <delay in ms>  (default: 1000ms)\n"
+                "         -w  wait until all tasks are ready for release\n"
+                "             (as determined by /proc/litmus/stats\n"
+                "         -f  <#tasks> wait for #tasks (default: 0)\n"
+                "\n",
                 error);
         exit(1);
 }
 
+ssize_t read_file(const char* fname, void* buf, size_t maxlen)
+{
+        int fd;
+        ssize_t n = 0;
+        size_t got = 0;
+
+        fd = open(fname, O_RDONLY);
+        if (fd == -1)
+                return -1;
+        
+        while (got < maxlen && (n = read(fd, buf + got, maxlen - got)) > 0)
+                got += n;
+        close(fd);
+        if (n < 0)
+                return -1;
+        else
+                return got;
+}
+
+void wait_until_ready(int expected)
+{
+        int ready = 0, all = 0;
+        char buf[100];
+        int loops = 0;
+        ssize_t len;
+        
+
+        do {
+                if (loops++ > 0)
+                        sleep(1);
+                len = read_file(LITMUS_STATS_FILE, buf, sizeof(buf) - 1);
+                if (len < 0) {
+                        fprintf(stderr,
+                                "(EE) Error while reading '%s': %m.\n"
+                                "(EE) Ignoring -w option.\n",
+                                LITMUS_STATS_FILE);
+                        break;
+                } else {
+                        len = sscanf(buf,
+                                     "real-time tasks   = %d\n"
+                                     "ready for release = %d\n",
+                                     &all, &ready);
+                        if (len != 2) {
+                                fprintf(stderr, 
+                                        "(EE) Could not parse '%s'.\n"
+                                        "(EE) Ignoring -w option.\n",
+                                        LITMUS_STATS_FILE);
+                                break;
+                        }
+                }
+        } while (expected > ready || ready < all);
+}
 
 int main(int argc, char** argv)
 {
         int released;
         lt_t delay = ms2lt(1000);
+        int wait = 0;
+        int expected = 0;
         int opt;
       
         while ((opt = getopt(argc, argv, OPTSTR)) != -1) {
@@ -27,6 +93,12 @@ int main(int argc, char** argv)
                 case 'd':
                         delay = ms2lt(atoi(optarg));
                         break;
+                case 'w':
+                        wait = 1;
+                        break;
+                case 'f':
+                        expected = atoi(optarg);
+                        break;
                 case ':':
                         usage("Argument missing.");
                         break;
@@ -37,6 +109,9 @@ int main(int argc, char** argv)
                 }
         }
 
+        if (wait)
+                wait_until_ready(expected);
+
         released = release_ts(&delay);
         if (released < 0) {
                 perror("release task system");